It is generally known that camshaft adjusters are used in internal combustion engines for varying the timing of the combustion chamber valves. Adjusting the timing to the instantaneous load reduces fuel consumption and emissions. Camshaft adjusters include a stator and a rotor. The rotor is usually connected in a rotatably fixed manner to the camshaft, the rotor being situated within the stator, coaxially with respect to same. The rotor and stator include oil chambers which may be acted on by oil pressure and generate a relative movement between the stator and the rotor.
To allow a torque transmission between the components of rotor and stator and also to compensate for a drive torque of the camshaft, a spring rotatably braces the rotor against the stator. This is described, for example, in German patent specification DE 103 61 509 B4 or United States patent specification U.S. Pat. No. 6,758,178 B2. In the cited publications, a coil spring is supported on each rotor by additional components or additional machining of the rotor. These additional parts or the additional machining increase not only the manufacturing costs, but also the assembly costs of a camshaft adjuster. In addition, the installation space for the coil spring is limited in the camshaft adjuster. However, since these known spring bearings require a relatively long axial installation length, installation of the coil spring in the rotor is therefore made more difficult.
In addition, it is generally known and customary in the prior art for these camshaft adjusters to include a cover that is situated on both sides of the “stator-rotor assembly.” These covers may have further functions in addition to a strictly sealing function. Thus, for example, they may be designed with gear teeth or with locking elements in order to be used as a chain wheel or as a locking cover. Regardless of which specific embodiment the cover includes, it is always designed in one piece. It is also known to fasten the above-described spring to the cover in order to brace the rotor against the stator.
For camshaft adjusters which provide a spring in the form of a coil spring, the coil spring is suspended in the cover and then fixed. For this purpose, a collar for spring suspension is necessary in the inner diameter of the cover. Due to the spring torque, the torsion spring in the spring suspension, which is formed as a punched or milled undercut (forming a web), is pressed against the cover collar, or axially and radially secured in a pressed-in pin. These known approaches using a cover with a drawn collar also have a number of disadvantages.